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| Nagasaki 9Aug45 |
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| "Fat Man" |
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| US B-29 Superfortress Bockscar and crew |
The atomic bomb "Fat Man" was dropped on Nagasaki 9Aug45 by the US B-29 Superfortress Bockscar [pictured with crew below]. It was modeled on "the gadget", the very first experimental atomic bomb detonated just a month before at the so-called "Trinity test"* in Socorro, New Mexico. The mushroom cloud resulting from the nuclear explosion over Nagasaki [above] rose 18 km (11 mi, 60,000 ft) into the air from the hypocenter. 80,000 were killed, half on the first day.
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| "Joe-1" |
So porous was the security at the Manhatten Project where all the intense work was done to accomplish the deed, that the first Soviet bomb, RDS-1 (a.k.a. "Joe-1" in reference to Stalin) was almost a direct copy, even in its external shape, of the US-developed Fat Man bomb. It was test-exploded a mere 4 years after the Nagasaki drop in Aug49.
Theodore Hall (1925-99), one of several physicists working at the time on the Manhattan Project eventually fessed up some 50 years later to divulging critical intelligence to the Soviets. He believed strongly (along with others, some caught much earlier, and executed for their deemed treachery) that an American monopoly on nuclear weapons was dangerous. He explained it this way in 1998, just before he died:
"I decided to give atomic secrets to the Russians because it seemed to me that it was important that there should be no monopoly, which could turn one nation into a menace and turn it loose on the world as ... as Nazi Germany developed. There seemed to be only one answer to what one should do. The right thing to do was to act to break the American monopoly".
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* This rare photo was taken at ground zero of the Trinity test site, after the bombing of Hiroshima and Nagasaki, and some time after the actual test. Oppenheimer, the so-called father of the atomic bomb, appears at the center in a light colored hat:
The US expected to have another atomic bomb ready for use in the third week of August, with three more in September and a further three in October.
ReplyDeleteAt exactly 8.15:17 a.m., the "Little Boy" was released from the bomb bay of the Enola Gay. The plane lurched upwards as the weight of the 9,000 lb bomb ceased to bear on it, but it still seemed to Ferebee as if the bomb was keeping pace with them. He watched through the nose as it began to fall away. It wobbled a little until it picked up speed, and then it went right on down just like it was supposed to. As the bomb left, Tibbets needed to get the Enola Gay as far from the bomb as posible. "I threw off the automatic pilot and hauled Enola Gay into the turn. I pulled anti-glare goggles over my eyes. I couldn't see through them; I was blind. I threw them to the floor".
ReplyDeleteThe bomb continued falling, its in-built radar methodically measuring the distance from the ground as it fell towards the T-shaped Aioi bridge, described by Tibbets as "the most perfect aiming point I had seen in the whole war"; its outer casing scrawled with messages from the 509th ground crew, including: "Greetings to the Emperor from the men of the Indianapolis." At 5,000 feet the barometric safety switch operated and, as the "Little Boy" reached 1,900 feet, the proximity fuse fired, sending the U235 bullet down the short barrel of the gun assembly into its U235 target. The super-critical mass was formed, drenched in neutrons by the polonium/beryllium initiator, and an uncontrolled chain reaction went through eighty generations before the expanding uranium core was too large to sustain it.
As Tibbets strained to get Enola Gay away to the south, "A bright light filled the plane." Watching, stunned, from his position in the rear of Enola Gay, Sergeant Bob Caron, the tail gunner, noticed a strange ripple in the air coming towards him. He tried to shout a warning but was too incoherent; the first shock wave hit them. Tibbets was astonished. "We were eleven and a half miles slant range from the atomic explosion but the whole airplane crackled and crinkled from the blast. I yelled "Flak!" thinking a heavy gun battery had found us".
Ferebee shouted. "The sons of bitches are shooting at us!". Caron saw the second shock wave. "There's another one coming!" Van Kirk thought the sensation was "very much as if you've ever sat on an ash can and had somebody hit it with a baseball bat . . . the plane bounced, it jumped and there was a noise like a piece of sheet metal snapping".
Tibbets realized what was happening. "Okay. That was the reflected shock-wave, bounced back from the ground. There won't be any more. It wasn't Flak. Stay calm".
Truman had mentioned an unspecified "powerful new weapon" to Stalin during the Potsdam conference. Towards the end of the conference, Japan was given an ultimatum to surrender (in the name of the United States, Great Britain and China) or meet "prompt and utter destruction", which did not mention the new bomb. Prime minister Kantarō Suzuki was to maintain silence[14] (mokusatsu, which was interpreted as a declaration that the Empire of Japan should ignore the ultimatum). Therefore the atomic bombs were dropped on Hiroshima on August 6 and Nagasaki on August 9, 1945. The justification was that both cities were legitimate military targets, to end the war swiftly, and preserve American lives. However, to some the timing has suggested that Truman did not want Stalin involved in the terms of Japan's surrender. It is important to note that Truman delayed the Potsdam Conference in order to be sure of the functionality of this "powerful new weapon."
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